MOVQ—Move Quadword

Opcode/Instruction	Op/En	64/32-bit Mode	CPUID Feature Flag	Description
0F 6F /r MOVQ mm, mm/m64	RM	V/V	MMX	Move quadword from mm/m64 to mm.
0F 7F /r MOVQ mm/m64, mm	MR	V/V	MMX	Move quadword from mm to mm/m64.
F3 0F 7E /r MOVQ xmm1, xmm2/m64	RM	V/V	SSE2	Move quadword from xmm2/mem64 to xmm1.
VEX.128.F3.0F.WIG 7E /r VMOVQ xmm1, xmm2	RM	V/V	AVX	Move quadword from xmm2 to xmm1.
VEX.128.F3.0F.WIG 7E /r VMOVQ xmm1, m64	RM	V/V	AVX	Load quadword from m64 to xmm1.
66 0F D6 /r MOVQ xmm2/m64, xmm1	MR	V/V	SSE2	Move quadword from xmm1 to xmm2/mem64.
VEX.128.66.0F.WIG D6 /r VMOVQ xmm1/m64, xmm2	MR	V/V	AVX	Move quadword from xmm2 register to xmm1/m64.

Instruction Operand Encoding

Op/En	Operand 1	Operand 2	Operand 3	Operand 4
RM	ModRM:reg (w)	ModRM:r/m (r)	NA	NA
MR	ModRM:r/m (w)	ModRM:reg (r)	NA	NA

Description

Copies a quadword from the source operand (second operand) to the destination operand (first operand). The source and destination operands can be MMX technology registers, XMM registers, or 64-bit memory locations. This instruction can be used to move a quadword between two MMX technology registers or between an MMX technology register and a 64-bit memory location, or to move data between two XMM registers or between an XMM register and a 64-bit memory location. The instruction cannot be used to transfer data between memory locations.

When the source operand is an XMM register, the low quadword is moved; when the destination operand is an XMM register, the quadword is stored to the low quadword of the register, and the high quadword is cleared to all 0s.

In 64-bit mode, use of the REX prefix in the form of REX.R permits this instruction to access additional registers (XMM8-XMM15). Note: In VEX.128.66.0F D6 instruction version, VEX.vvvv and VEX.L=1 are reserved and the former must be 1111b otherwise instructions will #UD. Note: In VEX.128.F3.0F 7E version, VEX.vvvv and VEX.L=1 are reserved and the former must be 1111b, otherwise instructions will #UD.

Operation

MOVQ instruction when operating on MMX technology registers and memory locations:
  DEST ← SRC;
MOVQ instruction when source and destination operands are XMM registers:
  DEST[63:0] ← SRC[63:0];
  DEST[127:64] ← 0000000000000000H;
MOVQ instruction when source operand is XMM register and destination
operand is memory location:
  DEST ← SRC[63:0];
MOVQ instruction when source operand is memory location and destination
operand is XMM register:
  DEST[63:0] ← SRC;
  DEST[127:64] ← 0000000000000000H;
VMOVQ (VEX.NDS.128.F3.0F 7E) with XMM register source and destination:
DEST[63:0] ← SRC[63:0]
DEST[VLMAX-1:64] ← 0
VMOVQ (VEX.128.66.0F D6) with XMM register source and destination:
DEST[63:0] ← SRC[63:0]
DEST[VLMAX-1:64] ← 0
VMOVQ (7E) with memory source:
DEST[63:0] ← SRC[63:0]
DEST[VLMAX-1:64] ← 0
VMOVQ (D6) with memory dest:
DEST[63:0] ← SRC2[63:0]

Flags Affected

None.

Intel C/C++ Compiler Intrinsic Equivalent

MOVQ:

m128i _mm_mov_epi64(__m128i a)

SIMD Floating-Point Exceptions

None.

Other Exceptions

See Table 22-8, “Exception Conditions for Legacy SIMD/MMX Instructions without FP Exception,” in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 3B.